Sex ratio at birth in twenty-first century Greece: the role of ethnic and social groups.

The number of male per 100 female live births (defined as the sex ratio at birth, SRB) has been shown to be consistently stable in human populations irrespective of time and geographical location. All over the globe approximately 105 boys are born for every 100 girls and any significant deviation from this 'global average' is considered to be unnatural and is attributed to sex-selective under-reporting of births, sex-selective abortion, sex-selective infanticide or other man-made factors. The present paper uses data on civil registration from 2004-2011 to investigate the sex ratio at birth in modern Greece. It was found that the SRB is extremely masculine when the parents originate from the Indian sub-continent and China. The SRB is also unnaturally high (more than 113 boys per 100 girls) in the case of legitimate births born to Greek mothers who are illiterate. These findings are strong evidence that sex-selective abortions are taking place in Greece within population groups with a certain ethnic and social profile. Other parameters, such as age of mother at birth, birth order, legal status of birth and geographical location, were also investigated and they were found to play a role in the variation of SRB, but not to the extent education and ethnic group do.

Novel carbon materials in biosensor systems.

In this work, novel carbon materials are evaluated as transducers, stabilizers and mediators for the construction of amperometric biosensors. It is shown that materials such as fullerenes and carbon nanotubes are promising materials as electrochemical mediators and enzyme stabilizers. Additionally porous carbon and porous glassy carbon are excellent transducers for amperometric measurements, while they provide cavities adequate for enzyme immobilization. At the same time, the sensitivity to peroxide is shown to depend on the activation procedures. Treatment that introduces oxygen groups increases the sensitivity of the carbon-based sensor to hydrogen peroxide considerably. These materials are used for the construction, mediation and stabilization of glucose biosensor.

Improved operational stability of biosensors based on enzyme-polyelectrolyte complex adsorbed into a porous carbon electrode.

A novel porous active carbon is utilized in order to adsorb the diethylaminoethyl-dextran (DEAE-dextran)-enzyme stabilized complexes, for the construction of highly stable biosensors. The interaction of DEAE-dextran with the examined enzymes increases dramatically the operational stabilization of the sensors, without adverse effects on the enzyme activity. At the same time, the porous active carbon allows for high enzyme loading, good electrical contact and low resistance throughout the sensing element. Glucose oxidase and horseradish peroxidase are used as model enzymes in this study to construct biosensors, with very good reproducibility (less than 5% RSD). As a result, the glucose sensor exhibits very long operational stability (over a period of 5 months), while the hydrogen peroxide sensor retains its initial activity after several weeks.